Telephone exchange system



June 9, 1931. I HZ HOVLAND 1,309,124

' TELEPHONE EXCHANGE sYsgEm Filed July 31, 1950-- ROTARYSTEF 7Nl/EN7'0H hi HQ VLAND' ATTORNEY o f'brushes but only one group relay perlevel."

V Patented June 9, 193.1

7 LABORATOBIE 5 The object ofthe'invention is tov improve such systems by providing a emore "eflicient I u V .only is sho'wnl Thisline-finder,LEllas two sets ofbrushes. mounted'onjone shaft 'eachr 'lset having access to the bank terminals ofag' r60 on which the terniinals-ofthe calling lineare YORK: q

,illpplication fire .nxly 3i, 7

This invention relates to telephone systems and more particularly to systemsin which automatic switches are employed in extende ing connectionsw 7 and economical arrangement for automati v cally extending a calling line to a first se lector switch. Heretoforeli equippedjwithtwo' sets of brushes, each set havin 'gaccess toa lOO-point bank, that is, a

bank having 10 levels a'ndlO sets ofterminals per level. In so'mecas'es one group relay has been provided for each 'level,fboth sets of brushes being efiecti've to hunt for the calling} line until the calling line has been found, In othercases two group relays have been provided foreach level, one for the lines connected f to terminals in the onefbanl; and

theother for the lines connected to terminals in the other bank the fsetv of brushes which has access to the -calling line are-renderedef; fective for seeking thecalling line to' the as both setsihave been advanced tothe level located 'thus obviating thenecessity for tes ing the terminals in'both bank's; Suchan arrangement shortens the time for finding; the j calling lin'e or permits "larger -'li;ne groups-V without increasingthe time for finding the One feature of"thisfinvention i's a line-'- v I That set" of brushes whichhas access to'a par- -'ticular calling line is rendered effective for seeking: the callingline, to the exclusion-[of the other set of brushes, as soon as the brushes have been advancedto-the level on which the Q 5 havinga capacity of 200 lines but the inventerminalszof the calling'lineiare located. J

The invention is illustrated in a system" using step-by-jstep .lineefinderj switches each tion' is applicable to any ffinder-rswitch equipped with two sets of brushes .and banks.

The drawing disclosesaline-finder switch embodying the features of: this invention and v also illustrates in dla'g rammat' cu manner a 1 TELEPHCNE nxc'rninen SYS EM I finder is permanently associated, v

d-B repre-e sent subscribers' stations "connectedfby' the l lines' l and 11 respectively,' to terminals in the banks of line-finder switches of which Tone ne-finder" switches have 1 been;

exclusion of the other set ofbrushes,las soon 1930.' Se ria1Eel 171,95??? V I o a first selector-switch with which the Referringto the drawing, A an grou er 100 :i-lines'.f1$ Theswitch includes a vertical stepping magnet"i23 for" advancing EEHRY HovLANb, wrnnrsronrnnmnnw ong, ssI QR B 'L s,-,ri ;rconronAmnn, or rrnw YORK, N. Y, 1A conrone'rrongorunnw v the-shaft andbrushes in vertical'movement',

a rotary stepping magnet 26 for advancing? :thdbrushes in arotary movement andarelease magnet 29 for ret'urnlng thezshrftaiid brushes to theirlnormal position.

The lines ofone group, includi l0 towhich'the brushes 41sec 42 haveacij'cess. ."Iheterminals o f-banks-fiOand lOare' V 1 arranged in", tenlevelsi'there being losers of .1;

terminals in each "level. The test or sleeve conductors for both groups of lines connect ng 111191; jareYconnected to terminals in'the' bank 3501700 which the brushes 31' and 32 have access jand l f the lines of the othergroup;'including"-the! line 11, are connected tote'rminals in theme};

brushes 33 and 43 have access, "The'terini-nalsl i shee a id 5rtk te ie iiiil beek ei e e f t s c wded om e ins -le calls in theusual'manner. V

The switehis refine equipiaeefvinnfa' vertlr cal commutator- 6Qj I'having5 10-segrnents," one .for each level of terminals "-i-n' the banks .30

and 40. ,Attachedto th ,;sh;aft;is:acommute-5,

tor brush '61; arranged to make Contact" sucessively with the commutator ,segnients, est-he shafti is 'step'ped ;1"1 p' f-rom;one level tq u 1 e i next, Whenever. a call"is originatedlover} line to which ithe' linegfinder has access; agrouild isconnected to the QQmmH J k g-Y 1 rendered effective, to the exclusion of the :inent corresponding to the level in which the terminals of this line are located so as to cause theline-finder' to stop when its shaft and brushes have been stepped up to this level. This ground connection is controlled by a single grouprelay (such as relay for all of the lines connected to the terminals of fthat level of both banks 30 and 40. This same group relay'isused in starting an idle N finder in search for the terminals of the callingline'. a

' Since but one of thetwo sets of brushes :has access to the terminals of aparticular llne, the requlred'set o'fbrushesmustbe H otherset, at orbefore the. finding of the terminals ofthe calling line, To this end the aforementioned groupvrelay is arranged to connect thefcorresponding commutator segment di rectly 'to' ground if the calling line is con-- 1 nected to terminalsin bank 40, and to connect 7 this segment to ground through a reslstance (such as the resistance 6) if-the. calling line is connected to terminals in the'bank 30. Whether or, not this resistance is included 'inzthe circuit through the commutator brush 61, when the shaft has beenstepped upto the level of the terminals ofthe calling line, controlsfa brush switching relay so that the proper'set of brushes will be effective to find the terminals of the calling line. 'VVhen the 2 selected setof brushes has been advanced by theoperation ofthe rotarysteppingniagnet into engagementwith the terminals of the calling'line the cut-through relay 27 operates to extend the connection from the line-finder brusheslto the associated selector T To describe the operation in detail assum "that-the subscriber atstation A initiates a V 4.0

call- "When the receiver is removed from the operates in an obvious circuit.

7 *windin'g. of grouprelay20 to battery. Line relay 2 also connects tsho-lding Winding, 1n

paralleljwith the. winding of thelcut-ofirrelay ithe upper contacts of the VON Springs to ground. Relay 24 opens the circuit through the winding of vertical magnet 23 thereby causing the release of magnet 23; but relay 24 is slow in operating so as to be sure that magnet 28 is fully operated before relay 24 v 3,;th r oughtheinner front contact of line relay ,over conductor 4, to thesleeve termin al f \line'lin bank 50.

I-n, operating, group relay 20 closes a circuit from ground through its right-hand throu h the front contacts, over conductor 21 lower back contacts of relay 28,,back contact "ofivertical ni'agnet23,norma.lly closed contacts ot theflOth yerticalstep springs, back con- -;,tactottherotaryinagnet26,'normally closed ...-.69

contacts. of the .lOth rotary stepsprings,

, lower winding of relay 22, and through the l upper'backcontact of relay 28-to battery.

Theclosing ofthis circuit is effective to operhate the interrupter relay 22: Relay 22Ccloses a circuit from ground through its'front conlOt'h vertical step springs.

tacts, the lower back contact of relay 24 and through the winding of vertical magnet 23 to battery. The vertical magnet 23 is thereby operated to advance the shaft and brushes of line finder 'LF up to the first level. The vertical off-normal springs VON are actuated when the shaft is stepped out of its normal position thereby connecting ground to conductor 34. The operation of 1nagnet'23 also opens the circuit through the lower Winding of relay 22, thereby causing the release of relay 22. The release of relay 22 opens the circuit through the winding of vertical magnet 23, thereby causing the release of magnet 23. The release of magnet 23 again closes the circuit through the lower winding of relay 22. Thus interrupter relay 22 and vertical stepping magnet 23 alternately operate and release to advance the shaft and brushes of linefinder LF until the level of the calling line is reached. e r

As shown in the drawing, line 1 is connected to terminals in the third level of bank 30 and the aforementioned operation of group relay 20 was, therefore, eflective'to connect ground through the back contact of cut-off relay 3, the outerfront contact of line relay 2, resistance 6, and through the left-hand front contact of relay 20, to the third segment of commutator 60. When the shaft and .lOth rotary step springs, lower winding of relay 22, and through the upper back contact of relay-28 to battery. Relay 24 operates but relay 25 is marginaland does not operate at this time. Relay 22 is held operated in this circuit geven'th'rough the Vertical magnet 23 has opened its back contact. Re-

;lay- 24 closes a locking circuit which may be (traced from battery through the upper back contactof relay 28, the upper winding and inner front contact of relay 24, and through opens the circuit through. the winding of .magnet 23. Thefreleaseof magnet 23- again closes the circuit through the lo'werwi'nding of relay 22, over conductor 21, to the ground .atwgroup relay 20. In case the calling line is connected "to term'inalsonthe tenth level, the" circuit through the wind-ingot relay 22 is maintained through the inner lower front contacts of relay 24, instead of through the Relay 24 also closesa circuit for operating the; rotary mag- .JOO

net 26 this :circuit mayfbe. tracedf f'rom battery through the winding or. magnet '26; Y the outer lower front contact 1 of relay 24, .to ground at the 'front contact of relay" 22. The 'operation of the rotary magnetadvances both sets of brushes into engagement with'the first set ofterminals'in' the previously selected-lev'el of 'both banks'30 and .40; Since'the marginalbrush switching relay. 25 was not operated, brushes 31,32Fand133 are efl'ectiye on thecall in questionxtofthe exclusion of brushes'i tl;42ranol l3; a. r

If the callingline is connectedto setofterminals in the selected level,.the, sleeve brush '33 finds I a distinguishing-p} tential on the sleeve terminal of (this set which is efiectiveto operateieut through re la-y27 andtojrprevent further advance ofthe brushes by holding relay. 22 .operatedl If the calling line is not connected to "the first'set of terminals-in the sele'ctedrlevel', the sleeve terminal tests idle 'or 'busy;depending upon Whether the line associated therewith is idle 'or. busy; but in either case,thejcut-through "relay 27 is not; operated and'the interrupter relay 22- is released by theoperati'on of the rotary magnet; The release :of relay 22, due

- tothe operation ofjm'agnet'26; opens the-cirreached." V "When 'brush 33 makes: contact with: the.

28: also opens; the circuit through thenpper {winding of relay 24.; and' relay2 l releases 9 cuit through the winding-of magnet 26 The release' of magnet 26 again closes the circuit for 'operatin'g relay 22 and the: reoperation ofrelay 22 closes 'thecirc uitform-operating ma'gn'etf26.-"f" Thus the interrupter; relay 22 and the rotary stepping magnet 26'alternate-. lyioperat'e and, release'to advancethebrushes vsuccessively from one "set of terminals to "the next: until the terminalslofthe calling linezare sleeve terminal of the =calling line; relay:- 22

is'held operated to prevent 'fu'rther advance of the "brushes; the circuit for holding relay withthe winding; oficut-ofl relay '3, inner front: :contact of relay .2; over "conductor 4:,

' sleeve "terminal an d brushl" outer "upper back contact of relay upperwback contact" of relay- 28'; lower i Winding of relay 27', and ithrough'ithe :upper'lwinding of relay 22 to ground. "-;'This circuit is also efiec-.

tive'to operate the cut-off relay 3, topartially- I I p I I {l ne-finderclrcuituntiltheconnect on lsil'erf i operate-the'cutethroughv relay 27,- and to hold- I, p I 7 leasedbythe calling subscrlb'eratwhich time j the liner'elay 2 op er'atedQr Relay 27' is ener gizedsufficiently to operate its-inner upper front contact and thuszclose a circuit from battery through its upper winding to ground at theouter upper front contact of relay 245;

the energizationof the'upper windingtof relay 27* causesthe; complete operation of this -lay 3 disconnects thefconducto'rs of line 1 :fromgthe windings oit'line relay 2,b'ut relay 2 1' energized in parallel with'the; windingof the 1 'cut-oiftrelay. [Thev operationof relay 3' also 'opens the. "circuit throughlthexwindin'g of group-relay 20 ,'and-the release ofrelayi2O Y disconnects the ground from. startfcon'ductor 21. NVithbrush'33 inlcontact with the sleev'e 7 terminal of line 1' the potentialof the sleeve Y 'ter minals ofthis line in the banks of 'alllinek 'finder and connector. switcheshaying access thereto is such as to indicate thatthei line is busy I and prevent. any other hunting linev finder or any. connector switch from. stopping f on 'th'e-t'erminals of this line. Y *5 The complete operation of Tel the. connection from linel. through its-jupper 'y ams- Y i 3 front? contacts to the windingsof lineirelayv" 71Lof-selector S; RelayifZl}opratesthereby causing the operation. of the :slowto-release; relay 7 2. Relay 72 connects aholding ground Y to the sleeve: conductorz35 so v'asl to holdlrelay 27 through its upper winding'independently be. trace.dk.from. battery through the upper contact of relay27, conductor34, to ground :atfl'therupper front; contact of "the "VON springs. Relay '28 opens the circuit. through the: upper winding of relay22 andop'ens'rthe ,95

circuit.through" the lowerv winding of relay 27. 5-Relay' 22 releasesfrsince. the circuit through:- its. lower :win'cling i-was previously 7 opened bythe operationof rotary magnet 26.- The' releas of .relay causes the release of f ;VVithrelay so aaataau eas est; ofirelayS;areheldoperatediby the'ground on 5} sleeve-conductorr85. Theopera'tion ofrelay was-opened atcommutator. brush 61. when the "multiple brushes were :-.rotated. intoi engage ment; with the first 'se'tpf terminals in thBiSG-i lectedgleveli WVith relay .,28;.operated-,F.the 1 startficonductor -21,1is extended, throughthe 7 middle lower ,front contact -.of relay28 ,-to a conductorfl'l' whichleads tothe next 'line' J -1 "i .finder inthe Y group ofi'linefinders haying} ,cess to the same lines as linefincler No further operation;takes;p1ace i 1 the selectors and connector through which the connection was completed;are-restoredto -nor 1nal,-'andthe holding ground '-is ',discon-. .5 nec'ted-from sleey'e conductor '35.}; .Line relay. 2a'nd cuteoflif relayf 3 are: thereby released-so Y that another call may beyinitiated or anfin- --;coming call received afistation AMRelay27 p also releases when the'gholdingground lis idis 7 connectedg .'from2'sleeye r conductor-35 thereby disconnectinglthe upperwinding-of'relay28 'doesnot "release'f since its holding windinggis eemthe ground atzthe? fronticontactj.

l of theVONsprjings; but relay 28 does not release at this time since this winding is also connected through the lower front contact'of the VONxsprings and through resistance. 86

i ci

tog round at the back contact of relay. 22. The release ofrelay 27 closes a circuit for operating release magnet 29; this circuit may be traced from battery through the winding of magnet 29, outer lower front contact of relay 28, outer lower back contact of relay 27*, inner upper back contact of relay 24, to

ground at the-Yupper front contact of the VON springspiThe operation ofmagnet 29 causes the' sh'aft and brushes to restore to 'normaL VVith the VON springs thus re- 'storedgto normal position, ground is disconnected" from conductor 34, thereby releasing magnet 29. Relay 28 now releases unless it vis held operated through its lower winding and inner frontcontactsto ground on starting. conductor 21; thus relay 28 cannot release if starting conductor 21 is grounded due to the origination of another call until thecalli ng line has been foundbysome other line-finder in the group. The release of relay '28 disconnects starting conductor 21 from conductor 37 and'from the lower winding of relay 28.-' The line-finder is now ready for usegon anothercall.

If a callis originated over a line connected {to terminals in the bank 40, it is necessary that brush switching relay 25 be operated.

Assuming a call to have been originated at station B, the opera'tion of group relay connects the third commutator segment through the left-hand front contact of relay 20, through the'outer front contact of line relay 12, to ground at the backcontactof cut "off relay 1 3. When commutator brush 61 makes'c'ontact with this commutator segment,

j the current through the upper winding of relayj operates this relay so a's to vrender "brushes 41, 42 and 43 efiective to the exclus'ionof brushes 31, 32'and 33. Relay25 looks through its'lower winding and front contact, over-iconductorfit, to ground at the upper frontcontact-'oftheVON springs. With this I rexception, the operation of line-finder L' F is m as h th all originated over a linefconnecteclito terminals located in bank I When the linefinder is "restoredto -nor V ma1,re1ay'25 isreleased.

In case the shaftand brushes are stepped up" 'tdthe 10th level and there is no ground potential I on the tenth commutator segment, relay-V 24 does not operate. .The circuit through 'theflower winding of relay 22 is opened at the 10th vertical step? springs and relay 22Qrel ases, thereby causing the immediate operation of relay 28. Relay 28 transferee'the starting conductor 21 to the next line finderin the'group; so thatthere willbe no delay in'starting' a finder switch 'in search for the'neXt-callingline, in. case another call is originated beforethe switch LF is restored-to normal. Since relays 24 and 27 have not been operated, the circuit for operating release magnet 29 is closed and the switch is immediately restored to normal.

In case the shaft and brushes are stepped around to the tenth set of terminals in any level and the line connected thereto is not the callingline, the upper winding of relay 22 is not energized; and, since the circuit through'its lower winding has been opened at the 10th rotary step springs, relay 22 releases. The release of relay 22 causes the lays one foreach of said groups of lines, means effective upon the operation of oneof said group relays for advancing said sets of brushes, in a primary movement to select the corresponding sub-groups, a circuit for stop ping said primary movement and for selecting one of said brushsets, and means for advancing said brush sets in a. secondary movement into engagement with the terminals of the selected sub-groups.

. 2. In combination, an automatic switch comprising a plurality of terminal banks, a set of brushesfor each bank, groups of lines each group comprising a plurality of subgroups-one for each of said banks, a group relay for each of said groups of lines, means efl'ective upon the operation of one of said group relays for advancing said brush sets in a primary movement to select the correspondmg sub-groups, a circuit controlled by said one of said group relays for stopping said primary movement and for selecting one of said brush 'sets,'and means for advancing said brush sets in a secondary movement into engagement with the terminals of the selected sub-groups.

3. In combination, a two-motion automatic switch having two sets of brushes and two banks of terminals, groups of lines, each 'groupcompr sing two sub-groups, the lines'of one sub-group be1ng connected todterminals in one of said banks and'the lines of the other sub-groupbeing connected to the correspondingly located terminals. in the other of said banks, group relays one for each of said groupszof lines, means effective upon the operation'of one of said group relays for advancing-the' brushes in a prlmary movement cuitefi'ective to stop said brushes upon reaching said corresponding sub-groups and effective to select one of said brush sets, and means for advancing said brush sets in a secondary to select the corresponding sub-groups, a cir- 7 nalsof the selected sub-groups.

movement into engagementwith the termi- 4. In a telephone system, a two-motion an tomatic switch having two sets of brushes one of said grouprelays effective'upon the I origination of acall over one of said lines 5 cess to the terminals of the calling-line'is ef 2 the exclusion of the set which access to theseterminals. V ,7 5. In combination, an automatic switch stopping the primary movement uponjreach-' for starting the operation of said switch, means for advancing the brushes of saidswitch in a primary movement to the two correspondinglylocated groups of terminals which include the terminals to which the calling line is connected, means for advancing said brushes in a 'secondarymovement into contact with the terminals of saidcalling line, and switching means for controlling the said two sets of brushes so that the set having acfective during said secondary movement to does nothave comprising two sets of brushes and two terminal banks, the terminals in each bank being arranged inten levels, groups of lines, each my name this 28th it 7, In a telephone system, an automatic switch ha'vingtwo' terminal banks, the terminals of each bank beingarranged-inten for switchingit'rom oneset'of brushes to the other, groups of lines each group compris-c ing two sub-groups, the lines of onesub levels, a set of brushes for each bank, a relayv I groupbeing connected to terminals in a parf ticular level of one of saidbanks'and the lines o of the 7 other sub-group being. connected to i terminals in the same level of the other of-said r I 1:

banks, a group rel'ay-for each of said groups of lines, means effective upon the origination of a call over'one of said lines for advancing said brushsets to the level of the calling line, a circuit for stopping the primary move-- 'ment uponreachingi-the' calling level, said circuit being effective to operate said switching relay if said calling line is connected to terminals in one of said banks and inefiective to operate said switching relay if said calling line isconnected to terminals in the other of sub-groups.

said banks, and means for advancing the brushes in a secondary movement into enigagemem' with t r na o t Selected 19. i

Inwitness whereof, I"hereunto subscribe I HENRY.HOVLAND.-

group comprising two sub-groups,-the lines of i Y I one Sub-group b ing connected to terminals in one level of one of said'banks and the lines of the other sub-group being connected to I terminals in thesame level of the other of said banks, a grouplrelay for each of said c groups of lines, means eflective upon theoperation of one of said group relays'for' ad? vancing the brushes in a primary movement to the corresponding level, a circuit controlled by said one of said group relays for ing said corresponding,-level,ia marginal relay in said circuit for selecting'a desired one V of said brush sets, and means for driving said brush sets in a secondary movement'i ntoengagement with the terminals in the two sub- 7 groups ofthe selected level;

6. In combination, an automatic switc having two terminalbanks, a set ofbrushes for each bank, a relay for. switching from one set of brushes to the other, groups oflines each groupcomprising a plurality of subgroups one for eachof said banks, a group relay for each of saidgroups of lines, means ef-' l fGClJlVQ upon the operation ofone of said group'relays for advancingsaid brush sets. 7 in'a primary moveinent'to select'the corresponding sub-groups,a circuit for stopping said primary movement' and for operating said switching'relay, and'means for advanclng said brushsets in a secondary movement intoengagement, with the terminals of the selected sub-groups. w 2+ 1 day of July, 1930.

. 'llO: Y 

